That statement is almost correct, but it needs a slight tweak!

Here's why:

* Minerals are naturally occurring substances. This is a key component of the definition.

* Minerals are solid. They have a definite shape and volume.

* Minerals have a definite chemical composition. This means they are composed of specific elements in a fixed ratio.

So, the complete definition is:

Minerals are naturally occurring solid substances with a definite chemical composition and a characteristic crystalline structure.

While it's true that minerals are composed of two or more elements bonded together in definite proportions, this is not the complete definition. It's important to include the other aspects like natural occurrence and solid form.